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<body><h1><a href="http://ejohn.org/blog/processingjs/">Processing.js</a></h1>
<h2>SineWave</h2>

<p>by Daniel Shiffman.  

Render a simple sine wave.</p>

<p><a href="http://processing.org/learning/basics/sinewave.html"><b>Original Processing.org Example:</b> SineWave</a><br>
<script type="application/processing">
int xspacing = 8;   // How far apart should each horizontal location be spaced
int w;              // Width of entire wave

float theta = 0.0;       // Start angle at 0
float amplitude = 75.0;  // Height of wave
float period = 500.0;    // How many pixels before the wave repeats
float dx;                 // Value for incrementing X, to be calculated as a function of period and xspacing
float[] yvalues;          // Using an array to store height values for the wave (not entirely necessary)

void setup() {
  size(200,200);
  frameRate(30);
  colorMode(RGB,255,255,255,100);
  smooth();
  w = width+16;
  dx = (TWO_PI / period) * xspacing;
  yvalues = new float[w/xspacing];
}

void draw() {
  background(0);
  calcWave();
  renderWave();

}

void calcWave() {
  // Increment theta (try different values for 'angular velocity' here
  theta += 0.02;

  // For every x value, calculate a y value with sine function
  float x = theta;
  for (int i = 0; i < yvalues.length; i++) {
    yvalues[i] = sin(x)*amplitude;
    x+=dx;
  }
}

void renderWave() {
  // A simple way to draw the wave with an ellipse at each location
  for (int x = 0; x < yvalues.length; x++) {
    noStroke();
    fill(255,50);
    ellipseMode(CENTER);
    ellipse(x*xspacing,width/2+yvalues[x],16,16);
  }
}
</script><canvas width="200" height="200"></canvas></p>
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<pre><b>// All Examples Written by <a href="http://reas.com/">Casey Reas</a> and <a href="http://benfry.com/">Ben Fry</a>
// unless otherwise stated.</b>
int xspacing = 8;   // How far apart should each horizontal location be spaced
int w;              // Width of entire wave

float theta = 0.0;       // Start angle at 0
float amplitude = 75.0;  // Height of wave
float period = 500.0;    // How many pixels before the wave repeats
float dx;                 // Value for incrementing X, to be calculated as a function of period and xspacing
float[] yvalues;          // Using an array to store height values for the wave (not entirely necessary)

void setup() {
  size(200,200);
  frameRate(30);
  colorMode(RGB,255,255,255,100);
  smooth();
  w = width+16;
  dx = (TWO_PI / period) * xspacing;
  yvalues = new float[w/xspacing];
}

void draw() {
  background(0);
  calcWave();
  renderWave();

}

void calcWave() {
  // Increment theta (try different values for 'angular velocity' here
  theta += 0.02;

  // For every x value, calculate a y value with sine function
  float x = theta;
  for (int i = 0; i &lt; yvalues.length; i++) {
    yvalues[i] = sin(x)*amplitude;
    x+=dx;
  }
}

void renderWave() {
  // A simple way to draw the wave with an ellipse at each location
  for (int x = 0; x &lt; yvalues.length; x++) {
    noStroke();
    fill(255,50);
    ellipseMode(CENTER);
    ellipse(x*xspacing,width/2+yvalues[x],16,16);
  }
}</pre>
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